Looking around at different cam/spring/retainer setups i will run on my D15Bvtec but wanna learn what all the "code" is about. I'm great at working on my civic but when it comes to blue-printing and precise engine work i'm sorta in the dark. I was wondering if someone could explain to me the importance of max lift and clearances. I want to make sure i don't buy a cam with too much lift and springs that don't compress enough. I thought it would be better that someone help explain this instead of me just posting another "will this setup work" thread, so i and others can benefit from it. For example, when a cam has 455in/430ex max lift, do the springs also have to have a max lift greater than 455? should the max lift of the spring be greater than or equal to that of the cam (450cam with 450 springs) or should you go over a bit on the spring size?(450cam with say a 470 spring). I just don't want to start the car only to discover the lift is SO HIGH the lobe wont rotate cuz the spring wont compress enough. Also, on NA engines, the more duration the better right? Cuz with FI you would just be blowing the charge out the exhaust valves on a high duration cam wouldn't you? And are light weight retainers interchangable? can you mix for example Skunk2 retainers with Zex springs with a Crower cam or will you start to run into more clearance issues? are they all the same size just manufactured differently or are they component specific, and meant to be used with a company cam and other company components? What about seat pressures? I've seen anywhere from 35lbs to 95lbs, do you want a low or high seat pressure for NA? Will a high seat pressure reduce valve float but take more effort from the engine to get the cam rotating?